Why did rich sultans kings and emperors collect animalsa: they waned to sell the to make moneyb: they wanted to prove their wealth and powerc: they traded these animals for other goods and servicesd: they used their fur to make goods?

The answer is, they wanted to prove their wealth and power.  The collection of these animals was called a menagerie. People in the higher level in society have a menagerie that has exotic animals. These animals are usually gifts from other royal blood which are rare and expensive to possess.